Add user blocking (#29028)

Fixes #17453

This PR adds the abbility to block a user from a personal account or
organization to restrict how the blocked user can interact with the
blocker. The docs explain what's the consequence of blocking a user.

Screenshots:


![grafik](https://github.com/go-gitea/gitea/assets/1666336/4ed884f3-e06a-4862-afd3-3b8aa2488dc6)


![grafik](https://github.com/go-gitea/gitea/assets/1666336/ae6d4981-f252-4f50-a429-04f0f9f1cdf1)


![grafik](https://github.com/go-gitea/gitea/assets/1666336/ca153599-5b0f-4b4a-90fe-18bdfd6f0b6b)

---------

Co-authored-by: Lauris BH <lauris@nix.lv>

models/migrations/migrations.go

@@ -560,6 +560,8 @@ var migrations = []Migration{
 	NewMigration("Add support for SHA256 git repositories", v1_22.AdjustDBForSha256),
 	// v287 -> v288
 	NewMigration("Use Slug instead of ID for Badges", v1_22.UseSlugInsteadOfIDForBadges),
+	// v288 -> v289
+	NewMigration("Add user_blocking table", v1_22.AddUserBlockingTable),
 }
 
 // GetCurrentDBVersion returns the current db version